Retrovirus PTERV1 linked to changes in chimpanzee brain development — ScienceAlert

A study led by Patricia Gerdes, a researcher at Lund University in Sweden, linked an ancient retroviral insertion, PTERV1, in the chimpanzee genome to suppressed activity of LINC00662. As ScienceAlert reports, the work was published in the journal Science Advances.

PTERV1 is found in chimpanzees and other African great apes, but not in humans. According to the researchers, around 4 million years ago, the retrovirus left a DNA insertion in the chimpanzee genome that has persisted to this day.

Impact on LINC00662

Humans and chimpanzees have the LINC00662 genetic region, which is active during early human brain development. Experiments indicate that it helps nerve cells mature and form extensions. In chimpanzees, the viral insertion suppresses LINC00662 activity.

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Humans and chimpanzees evolved from a common ancestor around 5–6 million years ago, and differences in their DNA amount to about 1.2%. At the same time, the human brain is approximately three times larger than the chimpanzee brain.

Organoid experiments

The team switched off LINC00662 in human brain organoids, laboratory models grown from cells. Under these conditions, neurons and their extensions, including dendrites and axons, matured and grew less actively than when LINC00662 activity was preserved.

In a separate experiment, removing the viral insertion from chimpanzee stem cells restored LINC00662 activity. The authors emphasize that this confirms the insertion's contribution to suppressing this region, but does not prove that its removal would alter chimpanzee brain development. Likewise, scientists cannot predict what the brain shape, abilities, or behavior of humans would be if they had a similar insertion.